Vehicle submersion detection device and method

Abstract

A vehicle submersion detection device for detecting vehicle submersion and facilitating occupant escape. The vehicle submersion detection device has a housing with a sensing cavity housing a sensing surface with a plurality of dielectric sensors. When the sensing cavity fills with water, a change in capacitive coupling at the plurality of dielectric sensors is detected indicating a submersion event. Detection of a submersion event may be used to trigger the creation of an occupant egress path.

Description

VEHICLE SUBMERSION DETECTION DEVICE AND METHOD CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to United States provisional patent application US63 / 774,241 filed on 19 March 2025, which is hereby incorporated by reference herein in its entirety.FIELD OF THE INVENTION

[0002] The present invention pertains to a device for detecting the submersion of a motor vehicle in a body of water. The present invention also pertains to a device for the detection of submersion in a fluid.BACKGROUND

[0003] Throughout the development of road vehicles, vehicle manufacturers have added safety features that have reduced collisions and prevented fatalities. Modern safety features include engineered glass, safety glass, as well as sensors that provide information about vehicle operating conditions and road or environmental conditions. Engineered automotive glass is designed to handle the strain of vehicle use as well as improve overall vehicle and occupant safety. In an example, laminated glass can be for the windshield and in other high impact applications. Tempered glass can be used for vehicle side and back windows and / or in applications as is it stronger and more resistant to impact than regular glass and, when broken, shatters into small, blunt pieces rather than sharp shards, reducing the risk of injury. Laminated glass can be made by applying a layer of polymer to a transparent glassy material, or by sandwiching a polymer between two pieces of glass. The polymer can act to chemically and mechanically bind two or more layers of glass, add strength to the glass, and / or make the glass resistant to projectiles and other stresses. Upon impact, laminated glass may break but the glass will often remains intact. Laminated glass used in many modern vehicles is resistant to blunt force and cannot be easily broken without a heavy and / or sharp instrument.

[0004] Despite the increased safety that laminated automotive glass provides, there are situations in which stronger glass increases the danger to motor vehicle occupants. Some road accidents result in vehicles entering bodies of water deep enough to fully submerge the vehicle, which can pose an entrapment risk. In particular, submerged car windows can be near impossible to break from the inside due to a combination of high strength glass together with the dampening effectand pressure of the surrounding water. During vehicle submersion, occupants typically have less than a minute to react and attempt to exit the vehicle, and failure to react quickly can result in occupant entrapment. Automatic detection of vehicle submersion and the subsequent creation of an escape path can reduce the risk of occupant drowning.

[0005] Submersion sensing devices in vehicles can protect vehicle occupants from drowning by detecting the submersion of a motor vehicle and controlling the vehicle to taking appropriate action to give the occupant a greater chance of escape and survival. In one example, United States patent US9,533,575B2 to Tran et al. describes a vehicle orientation device having a plurality of water level sensors which can be used to determine vehicle orientation when wading and calculate water depth on the vehicle body. In another example, United States patent US9,206,637B2 to Percher describes an automatic water sensor window opening system having a water collector with an inlet, a one way outlet, and a water sensor on the water collector for detecting water in the water collector.

[0006] Modem automobiles are increasingly complex and have numerous sensors to improve occupant safety and vehicle operations. There remains a need for a vehicle submersion sensor for detecting the submersion of a motor vehicle in a body of water such that action can be taken to increase occupant safety in the case of submersion.

[0007] This background information is provided for the purpose of making known information believed by the applicant to be of possible relevance to the present invention. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present invention.SUMMARY OF THE INVENTION

[0008] An object of the present invention is to provide a device that detects the submersion of a motor vehicle in water. Another object of the present invention is to provide a self-contained immersion detection device that provides reliable detection of life-threatening vehicle immersion events.

[0009] In an aspect there is provided a device for submersion detection comprising: a base comprising a power connector and bus connector connected to a reference voltage plane having a reference voltage; a plurality of dielectric sensing electrodes connected to the base to detect a change in the dielectric medium adjacent the dielectric sensors relative to the reference voltage;and a housing comprising a plurality of openings connected to the base and covering the plurality of dielectric sensors to provide a sensing cavity, wherein detection of the change in the dielectric medium adjacent the dielectric sensors indicates a submersion event.

[0010] In another aspect there is provided a device for submersion detection comprising: a base comprising a power connector and a bus connector; a sensing surface comprising a plurality of dielectric sensors, each of the plurality of dielectric sensors comprising a plurality of sensing electrodes, the plurality of dielectric sensors connected to the bus connector to detect a change in the dielectric medium above the sensing surface relative to a baseline; and a housing comprising a plurality of openings connected to the base and covering the plurality of dielectric sensors to provide a sensing cavity.

[0011] In an embodiment, the dielectric sensors are arranged radially, in a rectangle, cone, cylinder, or square on the sensing surface plane.

[0012] In another embodiment, detection of change in the dielectric medium adjacent the dielectric sensors triggers a control signal to lower of at least one of the windows in the vehicle.

[0013] In another embodiment, the device further comprises one or more of a heater, accelerometer, inertial sensor, gyroscope, pressure sensor, auxiliary sensor, and thermometer.

[0014] In another embodiment, the oscillation frequency of the plurality of dielectric sensing electrodes is between about 1 kHz and 10 MHz.

[0015] In another embodiment, the device further comprises a connection port to connect the dielectric sensing electrodes or the bus connector to a control system of a vehicle.

[0016] In another embodiment, the housing has a housing shape of a flattened cone, polygonal pyramid, square pyramid, triangular pyramid, hexagonal pyramid, polygonal frustum, dome, elongated cylinder, flattened dome, hemisphere, or elongated hemi-cylinder.

[0017] In another embodiment, the plurality of openings have an area of at least 1.0mm2.

[0018] In another embodiment, the device further comprises one or more bus regulator and microcontroller.

[0019] In another embodiment, the dielectric sensors or plurality of sensing electrodes create a base capacitance in the range of IpF to InF.In another embodiment, the device further comprises a protective coating on the sensing surface.

[0020] In another embodiment, the dielectric sensors comprise a mutual capacitance sensor.

[0021] In another embodiment, the device is connected to a communication means for communicating a signal through a cellular network or a satellite network.

[0022] In another aspect there is provided a method for detecting vehicle submersion comprising: detecting the presence of water at a plurality of dielectric sensors in a sensing cavity of a vehicle submersion detection device; determining whether the presence of water is indicative of a submersion event; and if a submersion event is determined, providing a control signal to a vehicle control system to open a vehicle egress for occupant escape.

[0023] In an embodiment, the vehicle egress is one or more of a window and sunroof.

[0024] In another embodiment, the method further comprises waiting a delay time between detecting the presence of water in the submersion cavity and determining whether the presence of water is indicative of a submersion event.

[0025] In another embodiment, the method further comprises providing a control signal for consequential actions based on the submersion event comprising one or more of displaying safety instructions on the car dashboard, providing audio instructions, and activation of other systems to improve occupant safety and protection.

[0026] In another embodiment, the method further comprises, before detecting the presence of water at the dielectric sensors, detecting an attitude of the vehicle, and if the vehicle is not in an upright position, closing the vehicle egress.

[0027] In another embodiment, the method further comprises sending an alert notification of one or more of potential flood, dangerous road conditions, water level mapping system, and risk to drivers.

[0028] In another embodiment, the alert notification is sent to one or more of an electronic traffic control system, emergency service, and mapping application.

[0029] Embodiments of the present invention as recited herein may be combined in any combination or permutation.BRIEF DESCRIPTION OF THE FIGURES

[0030] For a better understanding of the present invention, as well as other aspects and further features thereof, reference is made to the following description which is to be used in conjunction with the accompanying drawings, where:

[0031] Figure 1 is the perspective view of a vehicle submersion detection device;

[0032] Figure 2 is an top-down view of a vehicle submersion detection device;

[0033] Figure 3 is a side view of a vehicle submersion detection device;

[0034] Figure 4 is a perspective cross-sectional view of a vehicle submersion detection device;

[0035] Figure 5 is a perspective view of a device casing for a vehicle submersion detection device;

[0036] Figure 6 is a top-down perspective view of a dielectric sensor in a vehicle submersion detection device;

[0037] Figure 7 is a cutaway perspective view of a protective cover for a vehicle submersion detection device;

[0038] Figure 8 is a schematic illustration of the control components in a vehicle submersion detection device;

[0039] Figure 9A illustrates examples of dielectric sensor configurations on a circular sensing surface;

[0040] Figure 9B illustrates examples of dielectric sensor configurations on a square sensing surface;

[0041] Figure 9C illustrates examples of dielectric sensor configurations on a hexagonal sensing surface;

[0042] Figure 10 is a flowchart illustrating a method of submersion detection using the present vehicle submersion detection device;

[0043] Figure 11 A is a schematic illustration of a cross-sectional view of dielectric sensors covered in air; and

[0044] Figure 1 IB is a schematic illustration of a cross-sectional view of a dielectric sensor covered in water.DETAILED DESCRIPTION OF THE INVENTION

[0045] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0046] As used in the specification and claims, the singular forms “a”, “an” and “the” include plural references unless the context clearly dictates otherwise.

[0047] The term “comprise” and any of its derivatives (e.g. comprises, comprising) as used in this specification is to be taken to be inclusive of features to which it refers, and is not meant to exclude the presence of any additional features unless otherwise stated or implied. The term “comprising” as used herein will also be understood to mean that the list following is non-exhaustive and may or may not include any other additional suitable items, for example one or more further feature(s), component(s) and / or element(s) as appropriate.

[0048] As used herein, the terms “comprising”, “having”, “including”, and “containing,” and grammatical variations thereof, are inclusive or open-ended and do not exclude additional, unrecited elements and / or method steps. A composition, device, article, system, use, or method described herein as comprising certain elements and / or steps may also, in certain embodiments consist essentially of those elements and / or steps, and in other embodiments consist of those elements and / or steps, whether or not these embodiments are specifically referred to.

[0049] As used herein, the term “about” refers to an approximately + / -10% variation from a given value. It is to be understood that such a variation is always included in any given value provided herein, whether or not it is specifically referred to. The recitation of ranges herein is intended to convey both the ranges and individual values falling within the ranges, to the same place value as the numerals used to denote the range, unless otherwise indicated herein.

[0050] The use of any examples or exemplary language, e.g. “such as”, “exemplary embodiment”, “illustrative embodiment”, and “for example” is intended to illustrate or denote aspects, embodiments, variations, elements or features relating to the invention and not intended to limit the scope of the invention.

[0051] As used herein, the terms “connect” and “connected” refer to any direct or indirect physical association between elements or features of the present disclosure. Accordingly, these terms may be understood to denote elements or features that are partly or completely contained within one another, attached, coupled, disposed on, joined together, in communication with, operatively associated with, etc., even if there are other elements or features intervening between the elements or features described as being connected.

[0052] As used herein, the terms “dielectric sensor” and “dielectric sensing electrode refer to a dielectric change sensor that can detect and measure a change in electric field caused by the presence of a dielectric material. The dielectric sensor detects changes in the dielectricpermittivity of a surrounding medium by measuring capacitance, which is affected by the dielectric constant of the material above the dielectric sensor, in this case water or air. A dielectric sensor can detect a change in electrical signal or changes in the environment, such as the presence of water on the sensor in the case of a splash or submersion or immersion event.

[0053] Herein is described a vehicle submersion detection device capable of detecting submersion of a vehicle in water and providing a control signal to the vehicle to undertake a predictable action sequence to maximize the vehicle occupants’ chances of survival. The present vehicle submersion detection device allows water to flow freely in and out of a protective sensing cavity such that in the event of a submersion, a plurality of dielectric sensors in the sensing cavity will detect the presence of water. The vehicle submersion detection device can be connected to a primary control system or bus of a vehicle allowing it to use existing window and sunroof control systems and opening mechanisms such that the vehicle can perform an egress creating function. In addition to creating an egress path for the occupant, consequential actions from sensor triggering can include safety instructions guidance displayed on the car dashboard or sent to the occupants via audio instructions, or activation of other systems to improve occupant safety and protection.

[0054] Figure 1 is a perspective view of a vehicle submersion detection device 10. Connection port 12 provides a connection to the vehicle for power as well as data where the vehicle submersion detection device 10 can connect to, for example, a controller area network (CAN) bus of a motor vehicle. The connection port 12 enables transmission of power and data from the vehicle submersion detection device 10 to and from the vehicle’s control systems. Most modern vehicles generally use bus-based communication either with a CAN bus or CAN FD (CAN Flexible Data-rate) data protocol. The embodiment shown illustrates a standardized bus interface and power source over a typical 4-pin connector. Other types of interfaces may also be used, including but not limited to typical ODB-II connectors, terminal blocks, M12 circular connectors, Vehicle Control Units (VCU) proprietary connectors, Flat End Point (FEP) connector, and D-sub connectors. Other methods of non-wired connectivity may also be used to accommodate future standards of connection, which may include but are not limited to automotive ethemet, wi-fi and FlexRay™. While it is preferable that the sensor is powered froma wired connection, its power source provision could also be done through wireless induction making the sensor fully detached from any galvanic connection to the vehicle and yet be able to perform its operation. In this variant of the sensor, a wireless connection for the data interface is a logical complement to its isolated power source. Considering the low data rate of the sensor and limited messaging overhead, a LIN bus interface over various industry standard connectors can also be used. On the vehicle submersion detection device 10 side the connection port 12 is connected to a circuit board and to a controller.

[0055] A protective cover housing 14 covers the interior components of the vehicle submersion detection device 10, creating a sensing cavity into which water can enter such that it can come in close proximity with a sensing surface that protects the plurality of dielectric sensors tasked to detect a vehicle submersion. The plurality of cover openings 16a, 16b in the protective cover housing 14 allow entry and exit of water while also preventing larger debris from entering into the sensing cavity which could interfere with the sensing surface. This can happen for example in an accident where plastic or other foreign objects could become lodged near the sensing surface and affect the proximate dielectric properties. The protective cover housing 14 has a plurality of cover openings 16a, 16b through which water can flow into and out of the sensing cavity while providing an escape path for the initial volume of air. The protective cover housing 14 shown has a flat circular top surface and a sloping side, however the protective cover housing 14 may have a variety of other shapes that provide the function of water flow and air escape, protection of the sensing surface, and creation of a sensing cavity together with a device base 18. These may include, for example, domed, rectangular, or irregular shapes.

[0056] The protective cover housing 14 may be made of a variety of materials including but not limited to polymers, polymer blends, and coated metal or non-rusting metal. Polymer blends can also include conductive particles or fibers to reinforce the protection and add electromagnetic external field protection. The polymer blend material may also comprise, in some embodiments, a composite of polycarbonate and fiber glass reinforcement, or a nylon material with glass fiber reinforcements. Polymer blends and composites are typical in use in automotive enclosures where they are subject to a harsh environment and need the ability to tolerate impact and the large shear forces encountered in an accident. The protective cover housing 14 could also be made of or comprise aluminum, powder coated formed metal, or any other suitable material ableto maintain a cavity and provide the particle filtering function required in the present application. The production of such protective cover housing 14 may be done, for example, with injection molding techniques, vacuum forming, or by thermosonic bonding of a coated metal mesh over a plastic structure. 3D printing or urethane casting may also be used. The protective cover housing 14 shown has a flattened cone shape, but may be other shapes, including but not limited to a polygonal pyramid such as a square, triangular, or hexagonal pyramid, polygonal frustum, or elongated cylinder, flattened dome, hemisphere, or elongated hemi-cylinder. Any suitable shape for the protective cover housing 14 may be used, providing that it is capable of protecting an inner surface with dielectric sensing electrodes while allowing inflow and outflow of air and water through right-sized apertures.

[0057] The dielectric sensors in the presently described vehicle submersion detection device 10, which comprise sensing electrodes, are illustrated on only one side of the sensor, however a coaxial set of electrodes for example in a tubular assembly or a flat array of electrodes structured in a cylindrical housing may also be used. No matter the dielectric sensor configuration, the dielectric sensing surfaces should be protected inside a sensing cavity by a suitable protective cover housing 14 from accumulation of larger particles and abrasion to retain operation of the water immersion sensor device. The cover openings 16a, 16b shown have round, oval, and rectangular shapes, but may also come in different other shapes and sizes. The size of the cover openings 16a, 16b should be large enough to allow water flow within a few seconds of immersion but be small enough to keep debris and foreign bodies out of the sensing cavity.Cover openings 16a, 16b should have a sufficiently large size to enable water and air flow in and out of the sensing cavity without interference from turbulence or capillary forces or hydrophobicity interactions. In some cases, cover openings 16a, 16b smaller than 0.5 square mm of area are difficult to manufacture with molds and prone to clogging with small debris. Also, at that small dimension, water flow in the cavity can be limited. Cover openings 16a, 16b larger than a certain size will also tend to allow larger particles to get stuck in the cavity and when they are adjacent to the sensing surface and may affect the immersion detection. For these reasons, it is preferable that cover openings 16a, 16b be at least about 1.0mm in width and height. Round, polygonal, and slotted cover openings 16 a, 16b and combinations thereof with around 1 mm of width and 3-5 mm of length have been shown to offer good performance.

[0058] The protective cover housing 14 may be reversibly attached to the device base 18 using one or more different fastening mechanisms to create the sensing cavity, which may include but are not limited to screws, bolts, snap-fit, or adhesives. Other fastening methods that may be used include but are not limited to ultrasonic bonding or heat staking as these can offer fast and rugged methods to attach the protective cover at very low cost and with high throughput. Other design methods may include a press-fit approach where the top and bottom elements are designed with an interference fit and a large force is applied to the periphery of the sensor assembly to force the cover and bottom shell to snap together while pressing an internal sealing ring made of an elastomer. This assembly method provides both a way to securely close the enclosure, but also create a compression seal to protect the sensor internal electronics.

[0059] The device base 18 serves to hold and protect the components of the vehicle submersion detection device 10, which include the sensor surface, controller, circuit board, wiring, and other optional components such as, for example, one or more accelerometer, gyroscope, inertial angle sensor, inertial sensor, pressure sensor, thermometer, or similar auxiliary sensor. The device base 18 can be manufactured from any durable solid material including but not limited to one or more metal, alloy, polymer, or composite material, and may be made by, for example, 3-D printing, injection molding, form molding, or other forming method. The area near the connector pins should be insulated and the area near the sensing electrodes must be non-conductive. Preferably the device casing 18 is made of a material compatible with a two part design with the device casing 18 base and the device protective cover housing 14 that creates the full enclosure. In some embodiments the device protective cover housing 14 can be made from a polycarbonate and glass fiber blend or nylon and glass fiber blend. Preferably, the device housing material is non hygroscopic to avoid any effects of water interacting with the housing material affecting the dielectric sensing of the dielectric sensing electrodes. Metal may be used as part of the housing, however the areas adjacent conductive elements must be non-conductive, such as those near the bus connection pins and the sensing area. In some embodiments the device base 18 may be comprised of a single piece that may be over-molded over the inner components of the device, or it may comprise two or more complementary parts that would be joined together. The device protective cover housing 14 and device base 18 may also be a mix of plastic component and apotting compound to protect the electronics on the face opposite to the sensing electrode in the illustrated configuration.

[0060] The vehicle submersion detection device 10 may be attached to the vehicle via the device base 18 for example through a secure attachment that allows it to remain attached in the event of vehicle submersion. In some embodiments the fastening method can include one or more press-fit rivets that are snapped in place in indexing holes that are part of the car chassis or frame and that offer a positive retaining force. The vehicle facing side of the mounting surface of device base 18 can further be provisioned with a piece of very high bond adhesive such as 3M™ VHB™ tape that when applied at the factory complement the indexing rivets or snap-in pins to add a high bond to the vehicle chassis. This method of combining mechanical alignment with high strength adhesive offers the best compromise for efficient installation and long-term stability of the installation. Structural adhesives and other methods of ensuring a durable bond between the sensor casing and the vehicle may also be used and efficiently integrated in a production environment.

[0061] Figure 2 is a top-down view of a vehicle submersion detection device 10. Connection port 12 electronically connects the vehicle submersion detection device 10 to a bus or control system on a motor vehicle, allowing the vehicle submersion detection device 10 to communicate with other electrical systems within the motor vehicle such that the vehicle control system undertake an action sequence to control vehicle functions to maximize the vehicle occupants’ chances of survival in a submersion event. Connection port 12 is shown over-molded onto the rest of the device and attached to device base 18. Various types of connection systems and port types may be used to fulfill the function of the connection port 12, provided that they are appropriate for motor vehicle use. In the embodiment shown, the protective cover housing 14 is connected to the device base 18, and the protective cover housing 14 has through holes or apertures through which water can flow to the sensing cavity inside.

[0062] The device base 18 may be attached to the vehicle in various ways which may include but are limited to bolts, rivets, adhesives, and magnetic attachment. It is also possible to integrate this sensing structure as part of another element of the car system that is mounted against a sturdy area of the vehicle. The device base 18 can hold and protect different components of the vehicle submersion detection device 10 and may be any shape that will fit in the desired locationon a vehicle. The design of the device base 18 may take into consideration its placement on the motor vehicle with the size of the device dependent on the vehicle make and model, location of attachment, such that the device base 18 is large enough to contain the necessary components but small enough to fit into the space available at the desired location on the vehicle.

[0063] The vehicle submersion detection device 10 and dielectric sensor array, or plurality of dielectric sensors, is preferably placed in an area of the vehicle that is normally free of dust and particles and well protected by the car sturdy frame component such that it has good survivability in the event of an impact. The vehicle submersion detection device 10 is preferably mounted such that the connection port 12 and wires are directed towards the ground such that gravity will pull any water condensation or droplets away from the connector preventing a risk of corrosion of the connector. The vehicle submersion detection device is also preferably mounted in the vehicle above the maximal vehicle wading depth such as to activate only when the vehicle is very close to becoming buoyant when suddenly immersed in water. The sensor is also generally placed in the front of the vehicle as on most internal combustion engine, as this end of the vehicle has a natural tendency to be heavier and be faster submerged. The immersion sensor can also be placed in other areas of the car provided that when the car is near the flotation limits, water will be filling its sensing cavity. In some embodiments it is desirable to place the vehicle submersion detection device 10 near the engine compartment of the vehicle since this is the heaviest part of the vehicle and will be submerged first in the case of a submersion event. The exterior design of the mounting surfaces of the vehicle submersion detection device 10 preferably integrates poka-yoke design to prevent installation errors and make assembly and installation mistakes impossible or immediately obvious. Design factors for the present device can ensure that the sensor can only be inserted in the vehicle frame in the correct orientation. The same design principles apply to the various elements of the design such that there are no ambiguities in the position of the components during the construction. The vehicle submersion detection device 10 can further comprise one or more of a heater to prevent ice or moisture buildup, an accelerometer, inertial sensor, or thermometer.

[0064] The protective cover housing 14 has a plurality of cover openings 16a, 16b which may be of one or more different sizes and shapes. It is understood that the design and shape of the vehicle submersion detection device 10 shown is an example only, and that the presentlydescribed vehicle submersion detection device 10 may take a variety of different form factors, and be of varying shape and size. The detection cavity should be sized to allow free flowing of water and air into and out of the cavity but be small enough to fit onto the vehicle at the desired location. The exterior design is shown for a sensor that has a good compromise between height, water cavity capacity, low profile, durability, and overall integration limits of the electronic sensing system and communication bus. A smaller detection cavity may be triggered by a few drops of water which would trigger false positive while an overly large detection cavity would add unnecessary bulk to the submersion sensor device 10. Other design variants of the sensor include but are not limited to a sensing cavity that is elongated such that electrodes can be used to monitor a progression in immersion within the elongated cavity. This longer cavity would allow a measurement of the filling of the cavity while providing the desired sensor redundancy in a single sensing cavity. The automobile industry generally prefers more compact design as they can cut on weight and bulk, and right sized and right shape design can also be varied based on the make and model of the vehicle.

[0065] Figure 3 is a side view of a vehicle submersion detection device 10 and shows a connection port 12 and protective cover housing 14 with cover openings 16. The protective cover housing 14 shown can be reversibly attached to the device base 18 such that the interior components of the vehicle submersion detection device 10 can be accessed for, for example, replacement and / or cleaning. The connection port 12 shown features four pins, also known as pin connectors, comprising power supply pin 19 which serves as a power connector, communication pins 20a, 20b which act as bus connectors, and ground pin 21. The connection port 12, which serves as a bus connector through communication pins 20a, 20b, The pins in connection port 12 provide the vehicle submersion detection device 10 power supply through power supply pin 19 as well as communication through communication pins 20a, 20b, sometimes referred to as CAN high and CAN low, with electronic control units in the motor vehicle by way of the vehicle’s Bus or control system. The ground pin 21 acts as a return reference and can be attached to the vehicle chassis in some cases. Depending on the vehicle, the power supply pin supplies electricity with different voltages. For example, the power supply pin 19 can have a voltage of 12V for a typical motor vehicle. Trucks and larger equipment can have power supply pins 19 at higher voltages, typically 24V. The power supply pin 19 as shown or power connector may be powered by thevehicle battery and / or from an auxiliary power source. Communication pins 20a and 20b are used to transmit data and signals from vehicle submersion detection device 10. It is understood that the connection port may have three pins, i.e. a power supply pin, a communication pin, and a ground pin, or may have more than four pins. Other pin configurations of the connection port may also be used depending on the CAN, LIN, Ethernet, or other vehicle electronic system configuration.

[0066] A change in the dielectric, i.e. from air to water, sensed above the capacitance sensing surface relative a baseline is done by measuring the capacitance between a transmitter electrode and a receiver electrode. In a mutual capacitance sensor, the transmitter electrode is the driven signal and the receiver electrode is the sensing node, and together they form a capacitor. When the dielectric above the sensing surface changes to water, the effective dielectric constant increases, the electric field is redistributed, and the measured capacitance between the transmitter electrode and the receiver electrode changes relative to a baseline or reference. To detect the presence of water above the sensing surface the baseline is generally considered as the capacitance in the air condition. If there is no water above the sensing surface then the capacitance will be at the baseline. If water is present above the sensing surface there will be a significant increase in capacitance. Preferably, water sensing is done by detecting a change in capacitance above an absolute threshold where a capacitance reading above the threshold indicates the presence of water. Alternatively, continuous measurement or level sensing can be done where capacitance increases as water level rises above the sensing surface and the difference in capacitance relative to the baseline is an indication of water height above the sensor.

[0067] The vehicle submersion detection device 10 may be integrated into an original equipment manufacturer (OEM) vehicle during manufacture or may be added to the vehicle after original manufacture as a retrofit or augmentation of the vehicle capabilities. The vehicle submersion detection device 10 can preferably be adapted for use in motor vehicles of many different types with varying control system or CAN Bus architectures. Technological advancements in vehicle control systems invariably brings the adoption of other connection mechanisms and protocols, and the presently described vehicle submersion detection device 10 may be configured to connect with various connection mechanisms as needed to accommodate various vehicle controlsystems and protocols. In one embodiment, the vehicle submersion detection device 10 uses a power and bus connector that is compatible with the CAN Bus systems used in many modern vehicles. A CAN Bus generally connects electronic control units to each other on a vehicle and acts as a hub to receive and send control signals to and from connected devices. In the present device, detection of a submersion event sequence will trigger the vehicle submersion detection device 10 to send a control signal to the CAN bus indicating that the submersion event has occurred and execute a logic to act on the received control signal. Upon the detection of water in the sensing cavity by the submersion sensors, a control structure indicating a submersion event is sent from the device through the connection port 12 to one of the CAN Bus processing units of the motor vehicle, which can then, based on a control logic, send a further control message to electronic control units for the windows and / or sunroof, commonly referred to as the Comfort Unit, to open thus creating an egress path to allow the occupant(s) to escape. Depending on the specific car architecture, there can be one or multiple CAN Bus that are interconnected by bridges between them. In some architectures, the sensor can communicate with a control unit via CAN bus, but those messages can be re-transmitted using another protocol to the car Comfort Unit. In an alternative embodiment, a local interconnect network (LIN) connection interface can be used. The LIN connection comprises a LIN power supply pin, a LIN grounding pin, and a communication line.

[0068] Figure 4 is a perspective cross-sectional view of a vehicle submersion detection device with the interior sensing cavity 24 shown. The connection port 12 shown has a power supply pin 19 and communication pin 20 through which the vehicle submersion detection device communicates with and receives power from one of the vehicle’s buses. The connection port 12 is connected to a circuit board 22 which is held within the device base 18. The device base 18 may be over-molded or potted over the circuit board 22 in one continuous piece or it may be assembled from multiple pieces to enclose the circuit board 22. An array or plurality of dielectric sensor electrodes connected to or on the circuit board are protected by a portion of the device casing above the sensing surface 26. The sensing surface 26 may further comprise a protective and / or hydrophobic coating to protect the surface and inhibit molecular interaction of the protective surface with water. The protective coating covering the sensing surface 26 provides a water tight seal around the sensors but still allows detection of the change of electric field aroundthe dielectric sensors, where the electric field is capable of extending through the protective coating. An example of a protective coating that can be used over the sensing surface 26 includes a solder mask or protective film that comprises an insulative polymer such as an epoxy and a superhydrophobic nano-coating that can be deposited using vapor deposition or other commercial process. The superhydrophobic coating can condition the surface such that any condensation will easily wash out any debris and the sensing surface remains cleaner than if it were an uncoated polymer. Specific examples of hydrophobic coatings that may be used are Self-Assembled Monolayers of Phosphonates (SAMP) coatings, hydrophobic surface treatments applied via chemical vapor deposition (CVD), fluoropolymer or fluorosilane-based coatings, and silicone or silane-based coatings. Another example of a protective coating is to insert the printed circuit board with the capacitive sensing surface into a sealed cavity. The printed circuit board 22 and dielectric sensors may also be attached and sealed using VHB (very high bond) adhesive such that the electrodes are very close to the liquids with only a thin solder resist mask acting as the dielectric. Other coatings and protective layers or films through which an electric field will penetrate to enable the dielectric sensors or electrodes in the sensing cavity to detect the presence of water above the sensing surface 26 may also be used to protect the sensing surface 26.

[0069] The protective cover housing 14 is affixed atop the device base 18, creating the sensing cavity 24 which fills with water in the event of submersion through the cover openings 16a, 16b. The size of the sensing cavity 24 is based on the size and shape of the protective cover housing 14 and can be designed as desired to have a larger or smaller sensing cavity 24. The vehicle submersion detection device shown has a low-profile design and may be particularly useful for use in motor vehicles where space is limited. In the embodiment shown the height of the vehicle submersion detection device is about 21 mm, and the width and length are about 46 mm and about 70 mm respectively. The cavity can be made quite small in height yet retain its ability to detect water. However it is important that the cavity does not end up trapping water or small particles through capillary action and thus the volume of the cavity needs to have enough liquid capacity to allow flushing or cleaning in case of contamination by small particles that were able to enter through the holes or cover openings 16a, 16b in the protective cover housing 14. The device can be made bigger without affecting its performance, but larger volumes in the water detection area do not bring benefits and use more material and add bulk. Evolution inmicroelectronic integration may also decrease the size of the sensing device. The rugged connector used to interface between the sensor and other vehicle electronic systems also contributes to the size of the device. It is understood that any height, shape, or size of protective cover and housing may be used to accommodate for a variety of vehicle types, sizes, and mounting locations on the vehicle. The design of the vehicle submersion detection device embodiment shown provides a compact profile adaptable for various vehicle configurations.

[0070] One consideration in the design of the protective cover housing 14 is the ease with which water flows into and out of the vehicle submersion detection device. In a submersion event water should quickly flood the sensing cavity 24 when the vehicle is submerged. In the case of a splash, for example, any water entering the apertures in the sensing cavity 24 should be able to quickly flow out of the sensing cavity 24 when there is no submersion to avoid setting off a false submersion detection alarm. The detection of a potential submersion event is done at least in part by the plurality of dielectric sensors or dielectric sensing electrodes sensing the change in an electric field near the sensing surface 26. The dielectric sensors react to the presence of dielectric materials in the sensing cavity 24 through changes in mutual capacitance and, in some embodiments, with increased coupling with a ground reference area within the electrodes.Mutual capacitance in the presently described device occurs when water brought into proximity of the electric field above the sensing surface and dielectric sensors alters the mutual coupling and change in capacitance between the plurality of dielectric sensing electrodes in the dielectric sensors. A majority voting mechanism can be added to ensure that at least a certain number of dielectric sensing electrodes have detected the added dielectric presence, i.e. water in the sensing cavity 24. The detection of water as the dielectric, rather than air, by dielectric sensing electrodes, should persist and remain for a minimum duration of time, such as more than one second, to confirm a submersion. This method among other filtering done in the firmware ensures the discrimination between an accidental splashing of the sensor and a qualified submersion event.

[0071] In addition, the presence of an accelerometer and a gyroscope in or connected to the vehicle submersion detection device or connected to the vehicle CAN bus can complement the logic of automatic opening of windows in a vehicle immersion or submersion event to ensure that the vehicle is in a valid orientation and a stable state prior to activation. The accelerometerand gyroscope are not mandatory to obtain a submersion detection, but are typically used to make the unit capable of contextualizing the submersion and will not, for example trigger the opening of the windows if the system is not armed by the car electronic control unit (ECU). Vehicle-level detections from the vehicle submersion detection device can also be communicated to, via a communication network, for example, emergency providers, and / or other vehicles for pre-emptive hazard warning or dynamic rerouting, for example with traffic monitoring systems such as mapping application such as Google™ maps, Apple™ maps, or Waze™.

[0072] To mitigate risks of incorrect triggering of the submersion event, multiple elements can come into play. Mechanically, mist or droplets of water can be channeled away from the sensing surface by the combination of gravity and an inverted cone-shaped shield shown attached to the cover 14. This prevents sprayed water from directly contacting the sensing surface 26 as the water will be channeled around the surface and exit through lower channels outside the sensor. Small droplets landing on the sensing surface will have an effect on the electrode located on the printed circuit board (PCB) 22, but will not create as much dielectric variation due to the sensing being done by mutual capacitance between electrodes sensed through the protective dielectric of the enclosure and through the dielectric body. A small droplet will have a relatively minor change in mutual capacitance and that change will not be reflected across all the electrodes in a way to create the submersion detection. The electric field lines of the dielectric sensors on the sensing surface 26 go above just the detection sensing surface 26 and thus a larger dielectric like water filling the cavity has a more marked effect on mutual capacitance between sensing electrodes and contribute to enhancing the measurement resistance to interference. Condensation or small water droplets can end up on the sensing surface 26 and while their presence will be detected, their contribution will be far below the threshold to set off an alarm. In addition, in some embodiments that aim to have added safety, a majority voting system is setup in the control logic such that the presence of water needs to be confirmed on multiple instances to trigger the event. When there is no submersion, the sensing cavity 24 empties out through cover openings 16. When the sensing cavity 24 is filled, however, such as the case in a submersion event, the water within sensing cavity 24 will cover the sensing surface 26, which detects water via a change in the dielectric of dielectric sensors on the sensing surface 26.

[0073] Although the present vehicle submersion detection device is described having dielectric sensors, it is conceivable that in other embodiments, the device may additionally or alternatively comprise a plurality of electrodes or an electrode array structured over a piezoelectric material. Piezoelectric materials can help to create a surface acoustic wave that can be activated to remove surface water. In the event that the sensor is immersed, the piezoelectric resonance frequency can also be used to increase the detection performance, optionally or additionally using light and / or laser detection of water. Another possible way to sense the presence of dielectric can be using radiofrequency, which can serve as an additional or alternative to the dielectric sensing electrodes. By getting the whole cavity to resonate at certain frequencies, such as driven by antennas coming from the areas like the electrodes, radiofrequency (RF) coupling between paths may be detected that may lead to an alternative or additional means to detect water in the sensing cavity. A protective film or coating can be used to protect the electrodes that comprise the sensing surface 26.

[0074] Figure 5 is a perspective view of the interior of a vehicle submersion detection device with the protective cover or housing removed. Shown is the sensing surface 26 which detects submersion, or the presence of water inside the sensing cavity. Within the device base 18 are the electronic components that enable the submersion sensor device to detect the presence of water in the sensing cavity and connect the device to the vehicle for power and communication through connection port 12 for triggering events downstream detection of a vehicle submersion event. The present device can also optionally have on-sensor processing of the alarm sequencing and validation. The device base 18 shown has a protective component that is over-molded on top of a circuit board, electronic controller, and a plurality of dielectric sensors, where the dielectric sensors make up sensing surface 26. The over molding of the dielectric sensors protects the dielectric sensors of the sensing surface 26 and can increase the longevity of the device. In addition to the over molding of the dielectric sensors, a solder mask or polymer film can be used to protect the dielectric sensors. The sensing surface can be further coated with a superhydrophobic nano-coating or other water repellent coating such fluoropolymer coatings. These water repellent coatings can be applied using vapor deposition, dipping and curing, and other appropriate commercial processes. The water repellent nature of the protective coating can make it easier to keep the sensing surface clean. Coatings or films, thus applied, form a thin layerover the electrodes keeping them in proximity to the sensing surface 26 formed from the coating. The over-molding over the dielectric sensors secures and protects the sensing surface 26, which, when covered by water, changes the capacitive coupling and change in dielectric constant when the medium in contact with the dielectric sensor changes from air to water.

[0075] The dielectric constant of air is about 1, whereas the dielectric constant of water is about 80. The detection of an immersion or submersion event occurs because of the difference in dielectric constant between water and air, and detection of submersion occurs when the surface of the dielectric sensors in the sensing surface 26 detects a change in dielectric constant in relationship with the ground plane or across electrodes. Above a threshold, which differentiates between a splash and a complete submersion, the sensor logic will initiate the communication actions. Additionally, the presence of multiple dielectric sensors on sensing surface 26 can be used to determine if any one or more dielectric sensors are detecting a change in dielectric constant above a threshold, and use logic to determine that the submersion event has occurred if the sensor surface as a whole indicates a submersion. In some cases, detection of a change in dielectric constant above a threshold for all dielectric sensors in the sensing surface 26 will be indicative of a submersion event. In operation, when the dielectric constant of the material around a dielectric sensor can change, the capacitance of the sensor changes. The change in capacitance can detected, resulting in a signal that indicates that the device and therefore the vehicle has been submerged.

[0076] The shape of the sensing surface 26 is not limited and may be any reasonable shape and / or size to provide the desired threshold sensitivity. Adding multiple dielectric sensing electrodes ensures a certain level of safety redundancy. In principle a single electrode would suffice to properly detect immersion based on the change of capacitance, but this creates a single point of failure if the sensing circuit was to become inoperative for that dielectric sensor. Adding multiple dielectric sensing electrodes both increase the ruggedness of the detection but also ensures the ability of the system to monitor its internal state and take a majority voting which mitigate a single point of failure in the sensing mechanism.

[0077] Figure 6 is a top perspective view of a dielectric sensing surface 26 in a vehicle submersion detection device. In the embodiment shown, an array of dielectric sensors 28a, 28b, 28c make up sensing surface 26. Connection port 12 contains a power supply pin 19, a ground21, and communication pins 20a and 20b and is used to communicate with and receive power from the vehicle. Connection port 12 connects the vehicle submersion detection device to the CAN Bus or other control system of a vehicle such as a LIN connection to enable it to communicate with the different electronic systems on the motor vehicle and execute a control function to other vehicle components as needed. Different types of connectors may be used. Any number of pins 20 or connectors may be used as needed for connection to the vehicle. In one example, pin and sleeve connectors can provide stability and security and are durable under vehicle operation conditions. When connected, pin and sleeve type connectors form a durable and protective barrier. The pin and sleeve type of connection method is shown in the embodiment illustrated, however it is understood that any compatible connection type may be used. The connection port 12 is secured to device base 18 or may be part of the same injection process which protects dielectric sensors 28a, 28b, 28c, which are positioned in an array to make up sensing surface 26. The device base 18 secures and protects the components of the vehicle submersion detection device. Grooves 42 in the device base 18 can also provide openings through which water may flow into and out of the sensing cavity above the sensing surface 26 and used to expel air bubbles that would otherwise be trapped during submersion at some angles. When the dielectric material next to dielectric sensors 28a, 28b, 28c changes from air to water, the dielectric sensors 28a, 28b, 28c experience a change in capacitance due to a change in the electric field above the sensing surface 26.

[0078] The principle of operation of dielectric coupling relies on the strong difference in dielectric value between air and water. In addition, this method is reliable and amendable to many dielectric electrode configurations. Parallels can be drawn to commonly used capacitive touch buttons found in many consumer applications. The dielectric sensing electrodes in the present device can be driven directly from an on-board microcontroller or processing unit and can sense capacitance or dielectric changes directly using discharge monitoring and charge coupling between electrodes. Other robust methods introduce the capacitance between the electrodes in an oscillating circuit, and the frequency of oscillation can be measured continuously. Small changes in oscillation can be expected as the car or vehicle experiences changes in air pressure, humidity and temperature, however these are very small compared to adding the presence of water dielectric in the sensing cavity which will have a stronger effect onthe dielectric sensing electrodes, enabling signal differentiation between an immersion event and other changes in the sensing cavity. The oscillation frequency of the dielectric sensing electrodes is generally tuned to operate between 1 kHz and 500 MHz, or preferably between about 1 kHz and 10MHz. This frequency of operation ensures that the mutual coupling between dielectric sensing electrodes is used to its maximum potential without making the dielectric sensors too affected by environmental conditions. Shown are three dielectric sensors 28a, 28b, 28c arranged symmetrically in a round disc, which provides redundancy and ensures that submersion can be detected with a higher degree of certainty. A submersion event is detected when at least a majority of the dielectric sensors 28a, 28b, 28c within the array detect the presence of water within a threshold of detection of the dielectric sensor. Different numbers of dielectric sensors symmetrically or asymmetrically arranged in a variety of shapes may be used to achieve redundancy in the sensing surface 26.

[0079] Figure 7 is a cutaway perspective view of a protective cover for a vehicle submersion detection device. Protective cover housing 14 has cover openings 16 that can vary in shape. Shown are smaller circular cover openings on the flat top surface and larger elongated cover openings on the sloped sides. The cover openings 16a, 16b allow water to flow in and out of the sensing cavity on the vehicle submersion detection device. The protective cover housing 14 can function as a strainer for any large particles or debris, preventing material from entering the sensing cavity of the vehicle submersion detection device and interfering with or damaging the sensing surface and other inner components. The protective cover housing 14 may also function as a conductive shielding layer to prevent possible electromagnetic interference from reaching the dielectric sensors. The protective cover housing 14 may be manufactured by over-molding a mesh or structure with metal or plastic or by including conductive additives in plastic used during the manufacturing process. Any material and / or cover design that provides a straining effect and interference protection while creating a sensing cavity with a device casing or base may be used. An optional inner cover 30 inside the protective cover housing 14 can act as additional reinforcement to the protective cover housing 14 in its role in keeping out debris and particles and also potentially act as conductive shielding.

[0080] In operation, the vehicle submersion detection device may be exposed incidentally to larger amounts of splashed water such as in the event of driving through a puddle. The innercover 30 may provides additional protection to the dielectric sensors from exposure to water that is not from a submersion event. The inner cover 30 may be directly attached to the protective cover housing 14, it may be molded directly onto the protective cover housing 14 during the manufacturing process, or it may be attached by means of any number of fastenings. The inner cover 30 may be made of the same material as the protective cover housing 14 or a different material and may be used for its production. The dimensions of the inner cover 30 may vary in form and method of attachment to the vehicle submersion detection device.

[0081] Figure 8 is a schematic illustration of control components in a vehicle submersion detection device. Connection port 12 is connected to a circuit board 22 via bus regulators 34a, 34b. The connection port 12 transmits power to the vehicle submersion detection device and its various components through a bus regulators 34a, 34b component. The bus regulators 34a, 34b are used to protect CAN Bus connectors from brief high voltage events such as electrostatic discharge and may, for example, use an array of transient voltage suppression diodes. These diodes, in the event of electrostatic discharge, may offer protection by providing a low impedance path for the excess current to be diverted through. Bus regulators 34a, 34b can thereby manage power and communication from and to the CAN Bus by ensuring that the input voltage received from the motor vehicle’s power supply is converted and stabilized to levels required for the vehicle submersion detection device to function normally and safely. The connection port 12 is connected to a controller 36, which can be a microcontroller, which controls the operation of the vehicle submersion detection device. The controller 36 is connected to one or more dielectric sensor 28 on the sensing surface and can optionally be connected to one or more auxiliary sensors such as, for example, a temperature sensor 40 and / or an orientation sensor 38. In one embodiment, the controller 36 monitors the dielectric of the dielectric sensors 28 on the sensing surface and combines the data received from each of the dielectric sensors optionally with information from other sensors to determine if and when a submersion event occurs.

[0082] The controller 36 can also communicate with other electronic control units in the vehicle through the bus regulator 34 a, 34b and connection port 12 to enable the appropriate action(s) to be taken in the event of a submersion event. Typical controllers used in this type of application are automotive grade certified controllers that integrate the on-chip components that make thissolution cost effective to produce. Microcontrollers with built-in capacitive / dielectric sensing features can offer further cost reduction as those are commonly used to make capacitive buttons on low-cost consumer devices. The microcontroller would benefit from having a built-in CAN Bus controller and interface such as to minimize the number of components. Preferably the microcontroller integrates the necessary power management (DC step-down) circuitry to directly meet the stringent automotive power interface protection requirements such as to avoid external power regulation circuitry. The microcontroller can also have a bus interface to access an accelerometer, gyroscope, or orientation measurement data that is typically done externally to the microcontroller due to manufacturing process differences.

[0083] An array of dielectric sensors 28 are arranged on the sensing surface in a redundant configuration in the sensing cavity and can thereby be used to detect the presence of water in the sensing cavity. In one embodiment, change in dielectric of a dielectric sensor when air in the sensing cavity is replaced by water affects an oscillator circuit or radiofrequency (RF) circuit results in detection of a signal which indicates the change in dielectric. Any variation of dielectric properties near the surface of the capacitor indicates the presence of disruption of the normal air that makes up the sensing cavity. In this way, droplets, condensation are rejected based on their limited effect on the overall dielectric measurement. There is a majority voting system used to ensure that if a dielectric sensor 28 fails, it does not compromise the operation of vehicle submersion detection device.

[0084] One method to detect dielectric presence is generally known as mutual capacitance where the electrodes have capacitance coupling between them that creates field lines that cross the protection dielectric of the sensing cavity and those field lines pass in the air area of the sensing cavity. The PCB 22 containing the dielectric sensor 28 electrodes over a ground plane can create a base capacitance in the range of, for example, IpF to InF, or preferably in the 1-100 pF range. The mutual capacitance between the electrode and its neighbor can be a few pF in value. When a dielectric like water is added, there is a change of capacitance that is around 0.5 to 1 pF. The change in dielectric can be detected as a percentage of change that will be picked up by an oscillation circuit by changing its frequency. Microcontrollers have accurate clocking and use hardware counters, and these changes in frequency can be readily picked up. The controller 36 can also be connected to other components including the dielectric sensors of the sensing surface26, as well as other optional components including but not limited to one or more orientation sensor 38, temperature sensor 40, or inertial sensor. The inclusion of other sensors in addition to the sensing surface 26 can provide additional redundancy and thereby a higher level of confirmation of submersion in the case of a submersion event. A temperature sensor 40, one that is ideally quick reacting, may be used to detect a sudden change in the temperature to confirm an immersion event. For example, in near freezing temperatures, a strong change in dielectric coupled with a sudden change in temperature would confirm that the motor vehicle has entered a body of water. Different types of temperature sensors may be used, including but not limited to a self-contained digital temperature sensor mounted near or within the vehicle submersion detection device. The orientation sensor 38 may also be used to confirm a submersion event. For example, a 2-axis or 3-axis accelerometer or inertial sensor may be used to detect the gravitational field acting on the vehicle submersion detection device, which may change if the vehicle enters a flotation or sinking state. An orientation sensor may also identify the orientation and condition of the vehicle, confirming whether a submersion event has occurred. Other sensors may be used to detect changes in conditions that could correspond to a submersion event such as but not limited to a pressure sensor detecting a change in pressure that occurs when a vehicle is out of the water compared to when it is in the water.

[0085] Figures 9A, 9B and 9C illustrate examples of dielectric sensor configurations on circular, square and hexagonal sensing surfaces, respectively. Redundancy of dielectric sensor ensures the accurate detection of submersion events and prevents unnecessary actions from being initiated due to incidental contact with water. One example configuration of dielectric sensors is a symmetrical arrangement on the sensing surface. In Figure 9A, three possible configurations of dielectric sensors on a circular sensing surface array are shown with two, three, and four dielectric sensors. The embodiment of the device shown in the present specification uses a circular sensing surface with the use of three dielectric sensors in an array, however other shapes and numbers of dielectric sensors are possible. Figure 9B shows three possible configurations of dielectric sensors on a square sensing surface. Some of the possible configurations show the symmetrical arrangements of two and four dielectric sensors on the square sensing surface. Figure 9C shows three possible configurations of dielectric sensors on a hexagonal sensing surface. Possible configurations shown are the symmetrical arrangements of two, three, and fourdielectric sensors on the hexagonal sensing surface. Figures 9A, 9B, and 9C illustrate that any shape of sensing surface in combination with any configuration of dielectric sensor array can be used.

[0086] Figure 10 is a flowchart illustrating a method for immersion or submersion detection using the present vehicle submersion detection device. A vehicle submersion detection device attached to a motor vehicle detects whether water is present in the sensing cavity and at the sensing surface using a plurality of dielectric sensors 1002. If water is not detected, no further action is taken, and the detection is repeatedly attempted. With the detection of the water in the sensing cavity, a determination is made of whether the amount of water present reaches the threshold that indicates a submersion event 1004. The presence of water may represent a full submersion of the device where the sensing cavity is filled. Alternatively, a small amount of water may be present due to incidental exposure to water, such as from a puddle, or a car wash. A plurality of dielectric sensors are arrayed in the vehicle submersion device in a redundant arrangement. Most of the dielectric sensors must detect the presence of water for a submersion event to be determined to have occurred. This is an example of a threshold that must be met. If the threshold is met and a submersion event is detected, the logic queries whether it is safe to open a vehicle egress 1006, such as a sunroof or window.

[0087] There may be instances in which the opening of a vehicle egress during vehicle submersion can increase the danger that vehicle occupants are in. One such instance is in a case where a vehicle goes off a bridge or elevated road and rolls over in the air or before it hits water such that the vehicle may end up in an inverted position during vehicle submersion. In this case, having the windows closed at the moment of water impact may be advantageous, at least because curtain or side air bags will have a surface to provide support to the passenger in the case of an impact. In this case, closing the windows and sunroof prior to water impact may protect vehicle occupants and give occupants a better chance of survival in the case of an immersion event. Lightweight passenger vehicles have low centers of mass and are inherently stable in an upright position. If a vehicle enters a body of water in an inverted position while openings such as windows and / or sunroofs are closed, the vehicle will likely right itself before sinking in an upright position. When a vehicle is inverted during submersion and has an open egress such as an open window and / or sunroof, water ingresses at a fast rate and can completely fill a passengercabin with water in as fast as 12 seconds. In such an instance, if the vehicle remains inverted and does not right itself prior to sinking, this poses an increased risk for occupants who would likely be wearing seatbelts. If the vehicle logic detects that it is safe to open a vehicle egress such as during upright submersion, one or more of the motor vehicle window and / or sunroof can be opened to allow occupants of the motor vehicle to escape 1008. However, if the vehicle logic detects using preset pitch and roll parameters for measuring vehicle attitude that the vehicle is inverted during submersion and that it is therefore not safe to open a vehicle egress, the vehicle logic can determine whether any vehicle egress is open 1010. If there is an open vehicle egress, the vehicle logic can close the egress 1012, allowing the vehicle to right itself and then subsequently determine if it is safe to open a vehicle egress, If the threshold is not met, the control logic waits until it is safe to open a vehicle egress 1014, at which point vehicle window and / or sunroof is opened to allow occupants of the motor vehicle to escape. If no vehicle egress is determined to be open while the vehicle is inverted and the vehicle has not yet gained an upright attitude, there is a delay until it is determined that the vehicle is upright and it is safe to open a vehicle egress to enable an occupant to escape.

[0088] The logic of the presently described vehicle submersion system has several sensor-level strategies to mitigate false positives. The mechanical design of the protective cover housing only allows liquid water to enter the sensor’s cavity and prevents droplets, dirt, and splashes from entering. In addition, the electrode design aims for triple redundancy by preferably partitioning the electrodes into at least three sections, regardless of shape. In the system logic at least two but preferably all three or more than a majority of the electrodes should trigger in order to confirm that a critical immersion or submersion event is occurring. Finally, the location at which the sensor is attached to the vehicle is preferably above the wading water depth that the vehicle can safely bear. In addition, preset pitch and roll parameters measure vehicle attitude, specifically whether the vehicle is upright at the time of submersion detection. If the vehicle is upside down at the time of detection, the system logic will delay opening the side windows and sunroof until the vehicle is right-side-up to support correct timing of window lowering.

[0089] Upon detection of a water submersion, the vehicle, via a communication means, for example via satellite or cellular connection, can also notify other local vehicles and / or central dispatch of potential flood, dangerous road conditions, and / or risk to drivers and / or property. Co-location of the immersed or submerged vehicle can also be assessed to determine whether roadways are at risk and to notify appropriate authorities. In addition, multiple vehicle submersion incidents on roadways can help authorities use location and timing to map the incidence and path of water on roadways. Information can also be provided to private mapping applications to provide real time notification to drivers with information for other drivers to change their route to avoid the water. In another situation, the presently described water detection sensor on a parked car can detect rising water and activate the vehicle’s beacon or communication system. This can provide points of notification and flood mapping for emergency services and traffic mapping, particularly in urban and suburban areas with high car density. The ability of detection of water at a vehicle to detect and activate a beacon or communication alert notification also provides vehicle owners metadata proof for insurance claims and reduces the risk of fraud associated with resale of flood damaged vehicles. In instances of rising water or flood detection in a stationary vehicle with no occupants, vehicle sensors can confirm that the vehicle is not occupied and can take measures to open or close or leave windows as is as needed based on vehicle conditions.

[0090] Figure 11 A is a schematic illustration of a cross-sectional view a dielectric sensor in a vehicle submersion detection device in air as the dielectric, and Figure 1 IB is a schematic illustration of a cross-sectional view of a dielectric sensors in a vehicle submersion detection device covered in water as the dielectric. The schematic illustrations shown are not to scale and are for illustrative purposes only. The dielectric sensing electrodes 46a, 46b can be on a printed circuit board 22 with substrate 44 and covered in a protective layer 32 or protective coating. Each dielectric sensor shown comprises a plurality of dielectric sensing electrodes 46a, 46b which use mutual capacitive sensing to detect the presence of water by measuring changes in the capacitance caused by the presence of water near the dielectric sensors. Dielectric sensing electrodes 46a, 46b using mutual capacitance have a two-electrode pattern with a first dielectric sensing electrode 46a being a transmitter sensor and a second dielectric sensing electrode 46b being a receiver sensor. The complementary dielectric sensing electrodes 46a, 46b are coupled and form a tight electric field between them as shown. When covered in water, as occurs during a submersion event shown in Figure 1 IB, water in proximity to the dielectric sensing electrodes 46a, 46b causes a change in the coupling capacitance that is measurable. Water has a dielectricconstant that is about 80 times that of air and when water fills the space above the dielectric sensing electrodes 46a, 46b, there is a dramatic increase in the mutual capacitance signal. The high permittivity of water pulls more of the ringing lines downward confining them close to the sensor. Thus, when the vehicle submersion detection device comprising the dielectric sensors is submerged the signal received at the receiving electrode increases. A non-conductive gap 48 between the dielectric sensing electrodes 46a, 46b provides the electric field above the sensing surface. In the vehicle submersion detection device, the sensing circuit periodically charges and discharges the electrode and measures the resulting capacitance value. During an immersion or submersion event the presence of a water layer in proximity to the dielectric sensing electrodes 46a, 46b changes the dielectric constant between the dielectric sensing electrodes 46a, 46b. The system continuously monitors the capacitance, comparing it to a baseline. When a significant deviation from this baseline is observed, it is an indication that water has entered the electric field region of the sensor, indicating a submersion or immersion event.

[0091] All publications, patents and patent applications mentioned in this specification are indicative of the level of skill of those skilled in the art to which this invention pertains and are herein incorporated by reference. The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that such prior art forms part of the common general knowledge.

[0092] The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

Claims

CLAIMS:

1. A device for submersion detection comprising:a base comprising a power connector and a bus connector;a sensing surface comprising a plurality of dielectric sensors, each of the plurality of dielectric sensors comprising a plurality of sensing electrodes, the plurality of dielectric sensors connected to the bus connector to detect a change in the dielectric medium above the sensing surface relative to a baseline; anda housing comprising a plurality of openings connected to the base and covering the plurality of dielectric sensors to provide a sensing cavity.

2. The device of claim 1, wherein the dielectric sensors are arranged radially, in a rectangle, cone, cylinder, or square on the sensing surface plane.

3. The device of claim 1 or 2, wherein the device is mounted in a vehicle, and wherein detection of the change in the dielectric medium adjacent the plurality of dielectric sensors triggers a control signal to lower of at least one window in the vehicle.

4. The device of any one of claims 1-3, further comprising one or more of a heater, accelerometer, inertial sensor, gyroscope, pressure sensor, auxiliary sensor, and thermometer.

5. The device of any one of claims 1-4, wherein the plurality of sensing electrodes have an oscillation frequency of between about 1 kHz and 10 MHz.

6. The device of any one of claims 1-5, further comprising a connection port to connect the bus connector to a control system of a vehicle.

7. The device of any one of claims 1-6, wherein the housing has a housing shape of a flattened cone, polygonal pyramid, square pyramid, triangular pyramid, hexagonal pyramid,polygonal frustum, dome, elongated cylinder, flattened dome, hemisphere, or elongated hemicylinder.

8. The device of any one of claims 1-7, wherein the plurality of openings in the housing each have an area of at least 1.0mm2.

9. The device of any one of claims 1-8, further comprising one or more of a bus regulator and a microcontroller.

10. The device of any one of claims 1-9, wherein the plurality of sensing electrodes create a base capacitance in the range of IpF to InF.

11. The device of any one of claims 1-10, further comprising a protective coating on the sensing surface.

12. The device of any one of claims 1-11, wherein the dielectric sensors comprise a mutual capacitance sensor.

13. The device of any one of claims 1-12, wherein the device is connected to a communication means for communicating a signal through a cellular network or a satellite network.

14. A method for detecting vehicle submersion comprising:detecting the presence of water at a plurality of dielectric sensors in a sensing cavity of a vehicle submersion detection device;determining whether the presence of water is indicative of a submersion event; and if a submersion event is determined, providing a control signal to a vehicle control system to open a vehicle egress for occupant escape.

15. The method of claim 14, wherein the vehicle egress is one or more of a window and sunroof.

16. The method of claim 14 or 15, further comprising waiting a delay time between detecting the presence of water in the submersion cavity and determining whether the presence of water is indicative of a submersion event.

17. The method of any one of claims 14-16, further comprising providing a control signal for consequential actions based on the submersion event comprising one or more of displaying safety instructions on the car dashboard, providing audio instructions, and activation of other systems to improve occupant safety and protection.

18. The method of any one of claims 14-17, further comprising, before detecting the presence of water at the dielectric sensors, detecting an attitude of the vehicle, and if the vehicle is not in an upright position, closing the vehicle egress.

19. The method of any one of claims 14-18, further comprising sending an alert notification of one or more of potential flood, dangerous road conditions, water level mapping system, and risk to drivers.

20. The method of claim 19, wherein the alert notification is sent to one or more of an electronic traffic control system, emergency service, and mapping application.

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